Zinovy L. Rabinovich | History of Computing in Ukraine

Zinovy L. Rabinovich

Through more than 60 years of scientific work, Zinovy ​​Lvovich Rabinovich was a witness and an active participant in the creation and formation of digital computer technologies in Ukraine. He made a significant contribution toward the theory of electronic digital computers. Having started his career under the guidance of the eminent scientist, Sergey A. Lebedev, Rabinovich was involved in the engineering design of external devices for Small Electronic Calculating Machine - MESM, the first computer with programs stored in memory in continental Europe and the USSR. He was the chief designer of the second computer in Ukraine, SESM - the specialized computer created to solve systems of linear equations, which became the predecessor of the vector processors.

Zinovy Lvovich Rabinovich ​​was born in Kyiv on August 1, 1918. His father was a pediatrician and later became an honored doctor of the USSR, and his mother was a nurse. His father came from a very poor Jewish family with many children, and was the only one in his family to graduate from the University of St. Vladimir before the beginning of the Soviet regime. People called Lev Rabinovich "a doctor of God’s grace, " and he had an enormous influence on and love for people.

​​ Zinovy Rabinovich graduated, defending his thesis project in very extreme conditions. It was June 1941, the Great Patriotic War had broken out, and Kyiv was already being bombed. Being mobilized, Zinovy ​was sent to one of the defense enterprises in Kirov, where he began working at the series engineering design bureau.

After the war, he decided to return back home to Kyiv, with the intention of entering the graduate school at the Institute of Energy (later the Institute of Electrical Engineering) at the Academy of Sciences, USSR. On his first visit to Kyiv, Rabinovich passed the two qualifying exams for admission to postgraduate study. In 1947 he passed the rest of his qualifying exams and was accepted into graduate school, where S.A. Lebedev was his professor. Thus a new phase of his life began, associated with work under the direction of Sergey Lebedev.

Rabinovich characterizes his attitude to Lebedev in his memoirs as the following: "I can’t think of any better; for me he was God. And you don’t apply to gods any human estimates, so I do feel a certain uneasiness when talking about him, using the usual estimates of human qualities. He was special and difficult to compare with ordinary mortals. Interestingly, when I would address him, I felt as if I was speaking to God, as it happens in the mind of a believer - without any hesitation, immediately.”

By late 1948, under the orders of Lebedev, Zinovy ​​was working as an assistant in the creation of MESM. His job was to create a stand for the selection of the thermionic valves with the same specifications, a system of automatic stabilization of the valve filament, etc. Once the stand development was complete, he joined in the development of electronic computer hardware - high-speed cell structures, consistent arithmetic devices, etc. In addition, Z.L. Rabinovich had important independent work directly related to the creation of the MESM: namely, the development of a digital recorder output device.

For a long time Zinovy lived mostly in the laboratory of Feofania (Kyiv), coming home only on weekends. According to Rabinovich, only after the state commission approved MESM on December 25, 1951, was the “Feofanian" regime weakened.

Following Lebedev’s instructions, Z.L.Rabinovich, along with I.T.Parhomenko and Y.S.Mazyra, worked on developing a coherent arithmetic unit (AU) with four arithmetic operations. Subsequently, the developed coherent AU became part of a specialized electronic computer SESM, which was designed to solve the systems of linear algebraic equations and to calculate the correlation functions.

Under the recommendation of Lebedev, Z.L. Rabinovich headed the development of SESM, which was put into operation in 1956 and was the first computer with a vector processor in Europe.

The team of machine developers included a number of experienced laboratory staff: R.Y.Chernyak, A.L.Gladysh, I.T.Parkhomenko, and I.G.Okulova. The work began in the Feofania laboratory, where MESM was located.

For SESM they adopted a binary system with a fixed point. The number of digits after the decimal point was chosen to be 28. The negative numbers were represented in a direct code.

Based on the method adopted for the solution of linear algebraic equations (Gauss-Seidel) for SESM, the arithmetic unit (AU) performed only addition and multiplication (the basic algorithm of this method was the addition of paired pieces). AU included serial adder, four operational dynamic registers on a magnetic drum and a control circuit to monitor the operations and their precision. The addition time was 1.25 msec, while the multiplication took 17.5 msec.

According to Rabinovich, he considered himself to be a highly-qualified expert in the field of digital computing only after the completion of the SESM project, which greatly influenced his subsequent scientific work.

Following that project, Zinovy participated in a number of other significant projects. Together with B.N. Malinovsky, he developed the dual digital processing system for radar data (headed by Boris Malinovsky) and the target auto capture and its tracking (headed by Z.L.Rabinovich). V.M.Glushkov made a great contribution into the algorithmic software system, which was developed by Rabinovich. Following this, articles written by Rabinovich and Malinovsky that had previously been confidential were allowed to be published and received a warm response.

With Glushkov coming to head the laboratory, they experienced a change of direction toward the theoretical problems of digital computers. The main focus was the development of a computer to support and extend the theory of automata, which greatly influenced the subsequent work of Z.L. Rabinovich. From practical research, he switched to independent scientific research in the particular area - the Computer Science, as instructed by his leadership.

Rabinovich’s scientific team gave a formal definition to the subject of computer theory, which became an entry in the Encyclopedia of Cybernetics. Studying the theory of computers, Rabinovich introduced formal concepts of the hierarchical process of information processing for computers, with interaction between its levels divided into three groups - cell structure, the algorithmic structure and the architecture of computers. In summary, the obtained results were presented in the monograms such as "The basic computer operations" and "Foundations of the computer elemental structure theory.” The first of them acquired wide recognition among universities, where it was considered as “a teachers’ reference book.” This book was also popular abroad.

Zinovy ​​Rabinovich began to study the characteristics of interactive communication between human and computer. He was involved in developing the principles of high-level language (HLL) for the Small-sized computers, which was later used in the small-sized firmware computer MIR. Rabinovich’s department was drafting a project for a universal high-duty computer called "Ukraine," which unfortunately was never developed. Later, the principle of structural interpretation of HLL was used in a number of high-duty computers, including "Elbrus,” the first national supercomputer.

In addition to his own work in the area of computer technology, Zinovy ​​paid much attention to the question of human brain processes. According to him, it was his hobby to study cybernetics, science, and cognition, referring to the area of ​​human thinking. He was interested in the structural mechanisms and processes of thinking, especially in creativity. Gradually, from the arguments on the creative processes, Rabinovich moved to the nature of thinking in general. The results of his analysis were presented in a report, which Rabinovich presented at one of the prestigious symposiums. His performance and the conclusions received high praise from the national experts in neurophysiology.

Over the years, Zinovy ​​L. Rabinovich mentored many highly-skilled professionals, including 43 Associates of Science, 11 of whom later became doctors and world-known scientists.

Zinovy L. Rabinovich was a Professor, Doctor of Technical Sciences, Honored Scientist of Ukraine, and laureate of the State Prize of Ukraine, and he was awarded the Lebedev and Glushkov prizes of the USSR Presidium, and the medal, "For Valorous Labor in the Great Patriotic War 1941-1945.”

Rabinovich lived a long, productive life, and died in 2009 at the age of 91.